<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <button class="add">按钮</button>
</body>

</html>
<script>
//   class Preson {
//     constructor() {
//       console.log( this.name());
     
//     }
//     name(val){
//       // console.log(val);
//       return `姓名:${val.name}`
//     }
//   }
//  let preson= new Preson
//  preson.name({name:"张三"})
</script>